I have used Kingston, Sandisk and Transcend cards in my DP2M and DP3M both class 10 and class 4 without problems (and indeed see no significant improvement in write time in the class 10 over the 4). No corruption problems over about 6,000 exposures in total - except when the battery is coming to the end of its charge. Then I have seen some frames totally corrupted. My wholly uneducated guess is that as the battery charge begins to drop to exhaustion there is still enough power to power the camera but not enough to process the file and write it to the card. Changing batteries to a fresh one seemingly eliminates the problem.

pflower, I appreciate your reply. When you experience image corruption, is it a fragment written to card or when you open in SPP the image might show a JPEG but the X3F RAW will render as partially green-partially magenta file, or perhaps some thing else?

Sorry I also missed out from your original question the size of the cards. I mostly use 32gb cards but have various 16gb and even 4gb accumulated over the years. I haven't seen any discernable difference based upon size.

The number of corrupt images I have seen are very few - probably no more than 15 - 20 out of the 6,000 or so exposures taken. Mostly the xfr file is completely corrupted - from memory usually a brightish red/pink colour with snow and no indication of any image. Sometimes with a black dividing line half way through the frame. The same thing shows in the jpeg view.

Curiously I had a corrupt image yesterday which surprised me since the jpeg view was fine but clearly the raw file was corrupted. It looked fine in the thumbnail window of SPP and I batch processed all of the files to Tiffs and then imported into Lightroom. This one had a bright green overlay over the entire image - you could just discern that there was an image behind it. Going back to SPP the Review window also showed the same green overlay. I can't remember precisely the sequence of events but I certainly got a "battery empty" warning when shooting yesterday and had to change batteries. Whether or not that was at the same time as the corrupt image I can't remember and I have now deleted it so can't share.

Personal experience is that the camera and the cards I have are very reliable. As I said earlier the only problems I have had seem to me (purely based upon memory) related to the draining of the battery or, just possibly, overloading the buffer.

I have just bought the Merrill 1 and 2, taking advantage of the very cheap UK prices. I am using a Sandisk 8gb card. Having taken the cameras out twice now, several frames shot just before the battery expires have not been recorded on the memory card. One frame last night was recorded with a green/red overly divided by a black line. Also last night I was bracketing whilst the battery was very low and the camera froze. The only way to address this was to take the battery out and replace it with a fresh one, which appeared to corrupt not only the images I had just taken but several images taken just before. These images were just not recorded on the card. Strange. Earlier images on both occasions were recorded perfectly.

These were all raw files; I have not shot jpg. They are huge files and I guess use considerable energy to write to the card, perhaps exceeding what residual power remains in the battery. Just need to be careful as the battery winds down but a little frustrating nonetheless.

Thank you pflower and Geoff for your replies this is interesting information.

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Curiously I had a corrupt image yesterday which surprised me since the jpeg view was fine but clearly the raw file was corrupted. It looked fine in the thumbnail window of SPP and I batch processed all of the files to Tiffs and then imported into Lightroom. This one had a bright green overlay over the entire image - you could just discern that there was an image behind it. Going back to SPP the Review window also showed the same green overlay.

This is the problem I am occasionally encountering, followed by what Geoff also reports that a sequence of images can become entangled in the corruption issue, except in my case the battery is freshly recharged.

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Also last night I was bracketing whilst the battery was very low and the camera froze. The only way to address this was to take the battery out and replace it with a fresh one, which appeared to corrupt not only the images I had just taken but several images taken just before. These images were just not recorded on the card. Strange. Earlier images on both occasions were recorded perfectly.

Geoff raises an interesting point about high power demand scenarios which may exceed reserve power which in turn cause temporary failure of the camera. I guess one way to see if this is the cause is to swap in the AC-DC power unit and trying out similar image taking scenarios which tax power.

I have looked on the net for other that have experienced image corruption and there was one individual who was trying to taking bracketed panoramas that induced a similar issue. Here is that URL: http://www.dpreview.com/forums/thread/3500177

The fact that JPG is fine suggests that the problem is not battery charge nor SD card. (I ran Windows chkdsk on my card and my hard drive; no problem.) The constant pattern of failure - magenta and green divided by a horizontal line - strongly suggests a trouble point in the firmware processing that writes the strictly raw portion of the X3F file.

The questions for Sigma Corp.: what is this error, and is it initiated by a characteristic of the data of a shot or by something in the camera environment, such as the user pressing a certain button at a precise moment while the preceding shot is still being processed?

So what prompted your question in the first place? Are you getting significant numbers of corrupted files?

I have to say that I have been completely sold on these little cameras. Even if I were a working pro (which I am not) I would still trust them. I am just off to Venice and intend to take only the 2 Sigmas and a Mamiya 7ii whereas previously I would always take my Hasselblad. Given that here in the UK the price has dropped dramatically I am thinking of buying both of them again as back ups. The combination of the dramatic price drop and the imminent arrival of the Quattro might possibly point to a future discontinuance. Whilst the Quattro may be interesting I can easily fit both of these cameras in my jacket pockets. I have just done a series of A2 prints from the DP3M and the Hassy H3D-39. With careful processing the DPxM files come very close to the HD39s.

I still think that these little cameras are pushing above their weight and if you stretch them you can get problems. Both by making exposures when the battery is low or by making a series of exposures too quickly. I seldom do the latter but I will experiment over the next week.

Hi pflower, None of the threads elsewhere on the web seem to resolve in a definitive answer from the end user about what is going on here. I had been getting more corrupted images, so my camera is in for repair, I am not sure I can trust it anymore *if* this keeps cropping up. I have already had two saddening incidences where I can't just go out take the photo again. I turned to this forum in hopes that brand x memory card is at issue and not the camera. I too would really like to use this as my go to camera as I recognize what it can do but recent experiences have me questioning where to go from here.

When one talks about a sequence of images recently taken getting caught up in a corruption situation, one should remember that it takes the Sigma a long -- as in, very long -- time to write images to card. It wouldn't surprise me, if a corruption situation presents itself, to have a number of images, shot within the past minute or more, to be affected also. Once I have hit the buffer, with six or seven shots in quick succession, it takes an inordinate (by the standards of virtually any other modern digital camera) to write each image to card and thus clear the buffer for another shot. I haven't actually timed it, but I wouldn't be surprised to find a 10 second (or more?) write time for each image. I love the results from these cameras, and thus am resigned to living with this. Knock on wood, I don't recall a problem with corrupted files. --Barbara

I do appreciate that these cameras can take a long time to write a filled buffer to the card, though typically my corrupted images seem to occur when the display says the buffer can still accept between 5-6 shots available. Also, I am typically shooting in 2-second self timer. Sometimes when the light is good it might be then a series of 2-second timer captures in a row, not ever depleting the buffer that much, but I am modifying the control dials for Shutter/Aperture when this happens and card writing is taking place. One thing I have noticed is that perhaps when a X3F image corruption occurs the red writing light appears to stay on for an inordinate amount of time ( and that is relative to the idiosyncratic Sigma write times). Long write times don't bother me, as long as the RAW image data is actually properly written. Not sure if these "user inputs" are unintentionally interfering with the "multi-tasking" nature of the firmware. This may tie into what that one user I cited said about issues when taking panos.

For the sake of completeness what memory cards have you been using with good success?

I use SanDisk, 16GB. If I'm buying at the local Office Depot, I buy the fastest one they have. When I'm buying at my local camera store, I often get the next-to-fastest for a price savings, as I don't feel I need the fastest speeds now available. SanDisk cards have given me no trouble. --Barbara

I hope there's some way to get the issue across to Sigma Engineers regarding the battery running out while an image is being written to the card. It would be really nice for it run out of battery if it can't guarantee a complete shot.

The camera was repaired--essentially it seems Sigma changed out all the internals of the camera except the lens, shutter and metal housing. Thus far the issue has not resurfaced. Unfortunately, their replacement of parts introduced dust inside the camera which is visible on high f-stop photos so it needs to go back for that reason now...

So to summarize, the image corruption issue does not appear to be an issue with the battery nor memory cards, instead some unknown camera hardware defect. And since they swapped out several internal components it is not known which part or part combination caused the issue to surface.